APOE and Alzheimer disease: The ε4 allele of the ApoE-encoding apolipoprotein (ApoE4) is the main genetic risk factor for sporadic AD, and carriership of the ApoE4 risk allele has been linked to an oversupply of cholesterol, ensuing accelerated Aβ production (Lee et al, 2021), neuroinflammation (Ophir et al, 2005), impaired myelination (Blanchard et al, 2022), and tau-mediated neurodegeneration (Shi et al, 2017).